.NET下GDI＋的一些常用应用（水印，文字，圆角处理）

在某些情况下希望处理一些图片，比如

给图片添加一般文字：
原图

程序处理成


给图片添加水印：
原图

程序处理成


还有圆角效果：
原图

程序处理成


注：
（1）以下程序针对这个应用，也许这些对你没有用，但是基本的原理都差不多
（2）以上图为测试用，应该不算侵犯肖像权吧

程序界面：


程序点击这里下载。

如果需要提高图片质量，把
image.Save(sDstFilePath, ImageFormat.Jpeg);
改成

= ImageCodecInfo.GetImageEncoders()[0];
        myEncoder = Encoder.Quality;
        myEncoderParameters = new EncoderParameters(1);
        myEncoderParameter = new EncoderParameter(myEncoder, 100L); // 0-100
        myEncoderParameters.Param[0] = myEncoderParameter;
        image.Save(sDstFilePath, myImageCodecInfo, myEncoderParameters);
        myEncoderParameter.Dispose();
        myEncoderParameters.Dispose();

这是提高质量后的效果：


附一些关键代码：

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using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.IO; using System.Drawing; using System.Drawing.Drawing2D; using System.Drawing.Imaging;   public partial class Index : System.Web.UI.Page {     protected void Page_Load(object sender, EventArgs e)     {         if (!IsPostBack)         {             DirectoryInfo di = new DirectoryInfo(Server.MapPath(ConfigurationManager.AppSettings["uploadpath"]));             this.lb_ImageList.DataSource = di.GetFiles("*.jpg");             this.lb_ImageList.DataBind();         }     }     protected void btn_upload_Click(object sender, EventArgs e)     {         string sFileName = this.FileUpload1.FileName;         if (Path.GetExtension(sFileName).ToLower() != ".jpg")         {             ClientScriptManager csm = Page.ClientScript;             csm.RegisterStartupScript(this.GetType(), "", "<script>alert('System can only handle jpg file!')</script>");         }         else         {             string sFileFullPath = Server.MapPath(ConfigurationManager.AppSettings["uploadpath"] + sFileName);             this.FileUpload1.SaveAs(sFileFullPath);             this.lb_ImageList.Items.Add(sFileName);             this.lb_ImageList.SelectedIndex = -1;             this.lb_ImageList.Items.FindByValue(sFileName).Selected = true;             this.img_Src.ImageUrl = ConfigurationManager.AppSettings["uploadpath"] + sFileName;         }     }     protected void lb_ImageList_SelectedIndexChanged(object sender, EventArgs e)     {         this.img_Src.ImageUrl = ConfigurationManager.AppSettings["uploadpath"] + this.lb_ImageList.SelectedValue; ;       }     protected void btn_Generate_Click(object sender, EventArgs e)     {         string sFileName = this.lb_ImageList.SelectedValue;         string prefix = DateTime.Now.Minute.ToString() + DateTime.Now.Second.ToString();         string sSrcFilePath = Server.MapPath(ConfigurationManager.AppSettings["uploadpath"] + sFileName);         string sDstFilePath = Server.MapPath(ConfigurationManager.AppSettings["uploadpath"] + prefix + sFileName); ;         if (this.rb_Text.Checked)         {             try             {                 MyGDI.CreatePlainText(sSrcFilePath, sDstFilePath,this.tb_Text.Text,tb_Color.Text,tb_Size.Text,this.tb_Font.Text);                 this.lb_ImageList.Items.Add(prefix + sFileName);                 this.lb_ImageList.SelectedIndex = -1;                 this.lb_ImageList.Items.FindByValue(prefix + sFileName).Selected = true;                 this.img_Src.ImageUrl = ConfigurationManager.AppSettings["uploadpath"] + prefix+ sFileName;             }             catch (Exception ex)             {                 Response.Write(ex.Message);             }         }         else if (this.rb_Watermark.Checked)         {             try             {                 MyGDI.CreateWatermark(sSrcFilePath, sDstFilePath, this.tb_Text1.Text, this.tb_Color1.Text, this.tb_Size1.Text, this.tb_Font1.Text, this.tb_Text2.Text, this.tb_Color2.Text, this.tb_Size2.Text, this.tb_Font2.Text, this.tb_bgcolor.Text, this.tb_transparence.Text);                 this.lb_ImageList.Items.Add(prefix + sFileName);                 this.lb_ImageList.SelectedIndex = -1;                 this.lb_ImageList.Items.FindByValue(prefix + sFileName).Selected = true;                 this.img_Src.ImageUrl = ConfigurationManager.AppSettings["uploadpath"] + prefix + sFileName;             }             catch (Exception ex)             {                 Response.Write(ex.Message);             }         }         else if (this.rb_Corner.Checked)         {             try             {                 MyGDI.CreateRoundedCorner(sSrcFilePath, sDstFilePath, this.ddl_CornerLocation.SelectedValue);                 this.lb_ImageList.Items.Add(prefix + sFileName);                 this.lb_ImageList.SelectedIndex = -1;                 this.lb_ImageList.Items.FindByValue(prefix + sFileName).Selected = true;                 this.img_Src.ImageUrl = ConfigurationManager.AppSettings["uploadpath"] + prefix + sFileName;             }                      catch(Exception ex)             {                 Response.Write(ex.Message);             }         }     }     protected void btn_Delete1_Click(object sender, EventArgs e)     {         string sFileFullPath = Server.MapPath(ConfigurationManager.AppSettings["uploadpath"] + this.lb_ImageList.SelectedValue);         FileInfo fi = new FileInfo(sFileFullPath);         fi.Delete();         this.lb_ImageList.Items.Remove(this.lb_ImageList.SelectedItem);     } }   public class MyGDI {     public static void CreateWatermark(string sSrcFilePath, string sDstFilePath, string sText1, string sColor1, string sSize1, string sFont1, string sText2, string sColor2, string sSize2, string sFont2, string sBgColor, string sTransparence)     {         System.Drawing.Image image = System.Drawing.Image.FromFile(sSrcFilePath);         Graphics g = Graphics.FromImage(image);         g.SmoothingMode = SmoothingMode.AntiAlias;         g.InterpolationMode = InterpolationMode.HighQualityBicubic;         g.CompositingQuality = CompositingQuality.HighQuality;         g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias; //文字抗锯齿         g.DrawImage(image, 0, 0, image.Width, image.Height);         Font f1 = new Font(sFont1, float.Parse(sSize1));         Font f2 = new Font(sFont2, float.Parse(sSize2));         Brush brushfortext1 = new SolidBrush(ColorTranslator.FromHtml(sColor1));         Brush brushfortext2 = new SolidBrush(ColorTranslator.FromHtml(sColor2));         Brush brushforbg = new SolidBrush(Color.FromArgb(Convert.ToInt16(255 * float.Parse(sTransparence)), ColorTranslator.FromHtml(sBgColor)));         g.RotateTransform(-20);         Rectangle rect = new Rectangle(-image.Width/2-50, image.Height - 50, image.Width * 2, 40);         g.DrawRectangle(new Pen(brushforbg), rect);         g.FillRectangle(brushforbg, rect);         Rectangle rectfortext1 = new Rectangle(-image.Width/2 + image.Width / 5, image.Height - 45, image.Width * 2, 60);         for (int i = 0; i < 10; i++)             g.DrawString(sText1, f1, brushfortext1, rectfortext1);         Rectangle rectfortext2 = new Rectangle(-image.Width / 2 + image.Width / 5, image.Height -25, image.Width * 2, 60);         for (int i = 0; i < 10; i++)             g.DrawString(sText2, f2, brushfortext2, rectfortext2);         image.Save(sDstFilePath, ImageFormat.Jpeg);         image.Dispose();             }       public static void CreateRoundedCorner(string sSrcFilePath, string sDstFilePath, string sCornerLocation)     {         System.Drawing.Image image = System.Drawing.Image.FromFile(sSrcFilePath);         Graphics g = Graphics.FromImage(image);         g.SmoothingMode = SmoothingMode.HighQuality;         g.InterpolationMode = InterpolationMode.HighQualityBicubic;         g.CompositingQuality = CompositingQuality.HighQuality;         Rectangle rect = new Rectangle(0, 0, image.Width, image.Height);         GraphicsPath rectPath = CreateRoundRectanglePath(rect, image.Width / 10, sCornerLocation); //构建圆角外部路径         Brush b = new SolidBrush(Color.White);//圆角背景白色         g.DrawPath(new Pen(b), rectPath);         g.FillPath(b, rectPath);         g.Dispose();         image.Save(sDstFilePath, ImageFormat.Jpeg);         image.Dispose();     }       public static void CreatePlainText(string sSrcFilePath, string sDstFilePath,string sText, string sColor, string sSize, string sFont)     {         System.Drawing.Image image = System.Drawing.Image.FromFile(sSrcFilePath);         Graphics g = Graphics.FromImage(image);         g.SmoothingMode = SmoothingMode.AntiAlias;         g.InterpolationMode = InterpolationMode.HighQualityBicubic;         g.CompositingQuality = CompositingQuality.HighQuality;         g.DrawImage(image, 0, 0, image.Width, image.Height);         g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias; //文字抗锯齿         Font f = new Font(sFont,float.Parse(sSize));         Brush b = new SolidBrush(ColorTranslator.FromHtml(sColor));         Rectangle rect = new Rectangle(10, 5, image.Width, image.Height); //适当空开一段距离                for (int i = 0; i < 30; i++) //加强亮度             g.DrawString(sText, f, b, rect);         image.Save(sDstFilePath, ImageFormat.Jpeg);         image.Dispose();     }       private static GraphicsPath CreateRoundRectanglePath(Rectangle rect, int radius, string sPosition)     {         GraphicsPath rectPath = new GraphicsPath();         switch (sPosition)         {             case "TopLeft":                 {                     rectPath.AddArc(rect.Left, rect.Top, radius * 2, radius * 2, 180, 90);                     rectPath.AddLine(rect.Left, rect.Top, rect.Left, rect.Top + radius);                     break;                 }               case "TopRight":                 {                     rectPath.AddArc(rect.Right - radius * 2, rect.Top, radius * 2, radius * 2, 270, 90);                     rectPath.AddLine(rect.Right, rect.Top, rect.Right - radius, rect.Top);                     break;                 }               case "BottomLeft":                 {                     rectPath.AddArc(rect.Left, rect.Bottom - radius * 2, radius * 2, radius * 2, 90, 90);                     rectPath.AddLine(rect.Left, rect.Bottom - radius, rect.Left, rect.Bottom);                     break;                 }               case "BottomRight":                 {                     rectPath.AddArc(rect.Right - radius * 2, rect.Bottom - radius * 2, radius * 2, radius * 2, 0, 90);                     rectPath.AddLine(rect.Right - radius, rect.Bottom, rect.Right, rect.Bottom);                     break;                 }         }         return rectPath;     } }